XRF and TXRF - Features and benefits
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TXRF spectrometry is an analytical method that is very sensitive to ultra-low concentrations of elements in even minute sample amounts. It is capable of analyzing nanogram sample amounts with element concentrations ranging from 0.1 ppb to 100%.
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XRF and TXRF - Features and benefits
- 1. The Benefits of TXRF for Ultra Trace Element Analysis Innovation with Integrity Dr. Armin Gross Bruker Nano GmbH, Berlin, Germany August, 2016
- 2. TXRF – How does it work?
- 3. 3 Principles of EDXRF Background Energy-Dispersive X-Ray Fluorescence (EDXRF) analysis works in a 45°/45° geometry • Energy of X-ray photons Which element • Number of X-ray photons Quantitative analysis
- 4. 4 Samples for common XRF spectrometry • Solids (cut, polished and put into suitable shape) • Powders (as pressed pellets, fused beads or loose powders in liquid cups) • Liquids (in liquid cups) Necessary sample amount: from 1g to 10 g !! Principles of EDXRF Samples
- 5. absorption of primary beam and fluorescence radiation secondary fluorescence enhancement Ii = f (ci, cj) and ci = f (Ii, cj) Concentration needs to be determined with matrix matched standards DO YOU HAVE STANDARDS ??? Principles of EDXRF Quantification 5
- 6. 6 Principles TXRF spectroscopy Functional principle X-ray tube monochromator detector sample disc Total reflection X-ray fluorescence spectroscopy • Samples must be prepared on a reflective media • Polished quartz glass or polyacrylic glass disc • Dried to a thin layer, or as a thin film or microparticle Beam angle: 0o / 90o
- 7. 1. excitation spectrum 2. spectrum after prefiltration, filter component invisible here 3. emission spectrum of the tube 4. X-ray tube 5. monochromator 6. monochromatized excitation beam 7. detector 8. sample carrier 4 3 2 1 5 8 7 6 7 Key to TXRF sensitivity High signal to low background Monochromatization of X-ray beam leads to almost complete reduction of background
- 8. 8 Negligible absorption of primary beam and fluorescence radiation Negligible secondary fluorescence enhancement Ii = f ( ci ) ci = f ( Ii ) Samples are prepared as thin films or layers matrix effects are negligible Principles TXRF spectroscopy Matrix effects
- 9. 9 iIS ISiIS i SN SNC C Ci: Element concentration CIS: Internal standard concentration Ni: Element net countrate NIS: Internal standard net countrate Si: Element sensitivity factor SIS: Internal standard sensitivity factor Element sensitivity L-linesK-lines Atomic number Principles of TXRF Quantification Lack of matrix effect allows easy quantification by internal standardization
- 10. 10 Samples for TXRF • Powders: Direct preparation or as suspension • Liquids: Direct preparation • Always as a thin film, micro fragment or suspension of a powder • Necessary sample amount: Low µg respectively µl range Principles TXRF Samples
- 11. TXRF Spectrometer S2 PICOFOX S2 PICOFOX – Compact TXRF 11 • Most compact design portable, for on-site analysis • Fixed excitation mode easy to use, most suitable for teaching • >200 installations well established world wide technology • Attractive pricing most valuable TXRF solution
- 12. TXRF Spectrometer S4 TStar S4 TStar – Advanced TXRF 12 • Multiple excitation to detect most elements modes of the PSE • Large area detectors improved sensitivity for lowest limits of detection • Sample geometry measurement of discs, flexibility microscopy slides, wafers • Motorized beam path automatic beam adjustment and QC procedures • Large sample capacity up to 90 sample discs, multi-user operation
- 13. Rigaku Nanohunter II • Benchtop model • Mo X-ray tube, 600 W • 16 samples capacity GNR TX 2000 • Floor-standing model • Mo, W double target tube, 3 kW • 12 samples capacity 13 TXRF Spectrometer Other systems
- 14. Straight forward sample preparation
- 15. quartz glass glass carbon sapphire acrylic glass 15 acrylic glass quartz sapphire glass carbon Sample carrier Quartz glass carriers deliver lowest detection limits due to low background
- 16. fill sample in micro tube add internal standard homogenize Note: high matrix samples pipette on carrier may require a dilution step You‘ll need just a few steps for the preparation of liquid samples 16 Sample preparation Liquid and digested samples
- 17. dry by heat / vacuum load the instrument start data aquisition 17 Sample preparation Final steps
- 18. dilute sample with distilled water add internal standard homogenize pipette on carrier Suspensions can be analyzed just after dilution 18 Sample preparation Suspensions
- 19. fill powder in mortar grind carefully (<50 µm) weigh about 20-50 mg transfer to tube Solids are ground to fine particle size and resuspended for direct analysis without digestion 19 Sample preparation Solid and powder samples I
- 20. suspend in detergent solution add standard homogenize pipette on carrier 20 Sample preparation Solid and powder samples II
- 21. Sample preparation Microparticles dab vacuum grease on carrier pick-up some particles with a (glass) rod drop particles on grease Microparticles are measured semi-quantitatively and non-destructively 21
- 22. Current application areas Time for you to start with TXRF Environmental / Ecology Clinical Research / Biology Forensics Semiconductor Nanoparticles Food/Beverage Pharmaceutical/ Nutraceutical Plant Research 22